Compressor inlet duct

The present invention relates to an inlet duct for a compressor or supercharger.

Compressors or superchargers may be mounted to an internal combustion engine to increase the performance thereof. The compressor is operable to induct air through an inlet duct to interleaved and counter-rotating first and second rotors. The first and second rotors cooperate to increase the volume of air communicated to the internal combustion engine, thereby increasing the volumetric efficiency of the internal combustion engine.

An inlet apparatus for a compressor having a housing defining a generally C-shaped inlet opening and a rotor cavity configured to contain interleaved, counter-rotating first and second rotors is provided. The inlet apparatus includes an inlet duct positioned upstream of the compressor and defining an inlet opening and a generally C-shaped outlet opening. The inlet duct has an inner wall defining a cavity operable to communicate airflow between the inlet opening and the generally C-shaped outlet opening of the inlet duct. The generally C-shaped outlet opening of the inlet duct is substantially similar to the shape of the generally C-shaped inlet opening of the housing. The inner wall includes a floor portion and a roof portion each extending from the inlet opening to the outlet opening. At least a portion of the floor is contoured to impart a velocity component to the airflow complementary to the tangential velocity of each of the first and second rotors during rotation of the first and second rotors.

The inlet duct may further include first and second ridges formed centrally on the respective floor and roof portions each extending toward the outlet opening of the inlet duct. The first and second ridges preferably increase in at least one of height and width moving toward the outlet opening of the inlet duct. The first and second ridges are operable to impart a velocity component to the airflow complementary to the tangential velocity of each of the first and second rotors during rotation of the first and second rotors.

The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.

FIG. 1 is a bottom view of a portion of a supercharger or compressor having an inlet duct mounted thereto;

FIG. 2 is a perspective view of the compressor of FIG. 1 , with the inlet duct removed, illustrating a first and second rotor;

FIG. 3 is a perspective sectional view of the inlet duct of FIG. 1 ; and

FIG. 4 is a perspective view of an alternate embodiment of the inlet duct of FIGS. 1 and 3 , illustrating an alternate position for a bypass passage.

Referring to the drawings wherein like reference numbers correspond to like or similar components throughout the several figures, there is shown in FIG. 1 a supercharger or compressor assembly 10 . The compressor assembly 10 is configured to mount to an internal combustion engine, not shown. Those skilled in the art of engine design will recognize that the compressor assembly 10 can be used to increase the volumetric efficiency of an internal combustion engine, thereby increasing the performance thereof. The compressor assembly 10 includes a compressor 12 and an inlet duct 14 . The compressor 12 includes a housing 16 configured to contain internal components of the compressor 12 . The housing 16 is preferably formed from cast metal, such as aluminum or magnesium. The inlet duct 14 is mounted to the housing 16 via a plurality of fasteners 18 . The inlet duct 14 may be formed integrally with the housing 16 . The inlet duct 14 is preferably formed from cast metal such as aluminum or magnesium; however, the inlet duct 14 may be formed from a plastic or composite material while remaining within the scope of that which is claimed.

A throttle body 20 is mounted with respect to the inlet duct 14 and is operable to vary the amount of airflow, indicated as arrow 22 , entering the inlet duct 14 . A bypass assembly 24 is mounted with respect to the inlet duct 14 and is operable to selectively divert airflow 22 from the compressor 12 during certain modes of engine operation, such as light load engine operation. The bypass assembly 24 includes an actuator 26 operable to selectively and variably open a valve 28 disposed within a bypass passage 30 defined by the inlet duct 14 .

Referring to FIG. 2 , and with continued reference to FIG. 1 , there is shown the compressor 12 with the inlet duct 14 removed. The housing 16 defines an inlet opening 32 . The inlet opening 32 is generally C-shaped in form and is operable to communicate airflow 22 to a rotor cavity 34 . The rotor cavity 34 is defined by the housing 16 and is configured to contain a first and second rotor 36 and 38 , respectively, therein. The first and second rotors 36 and 38 are interleaved and are rotatably supported within the rotor cavity 34 by a rotor bearing support 39 . The rotor bearing support 39 is formed integrally with the housing 16 . The first and second rotors 36 and 38 counter-rotate as indicated by arrows 40 and are operable to convey volumes of air from the inlet opening 32 to an outlet opening, not shown, for subsequent introduction to the internal combustion engine.

Referring to FIG. 3 , and with continued reference to FIGS. 1 and 2 , there is shown a sectional view of the inlet duct 14 of FIG. 1 . The inlet duct 14 has an inner wall 42 that defines a cavity 44 operable to convey airflow 22 between an inlet opening 46 and an outlet opening 48 , each defined by the inlet duct 14 . The inner wall 42 includes a floor portion 50 and a roof portion 52 . Additionally, a sidewall portion 54 interconnects the floor portion 50 and the roof portion 52 . A portion 56 of the floor portion 50 is raised in the area of the rotor bearing support 39 , shown in FIG. 2 , such that the outlet opening 48 is generally C-shaped and substantially similar to the shape of the generally C-shaped inlet opening 32 of the housing 16 . As shown in FIG. 3 , the portion 56 of the floor portion 50 is raised immediately downstream from the throttle body 20 and increases in height toward the outlet opening 48 . Portions 58 of the floor portion 50 are contoured to impart a velocity component to the airflow 22 complementary to the tangential velocity of each of the first and second rotors 36 and 38 , shown in FIG. 2 , during rotation of the first and second rotors 36 and 38 . For instances where the inlet duct 14 is formed separately and mounted to the housing 16 , the perimeter of the outlet opening 48 of the inlet duct 14 should be at or within the contour of the generally C-shaped inlet opening 32 to avoid the potential for turbulence caused by mismatch between the two components.

A first ridge 60 is formed centrally on the floor portion 50 and extends toward the outlet opening 48 of the inlet duct 14 . The first ridge 60 is preferably formed with a generally triangular cross-section with increasing height and width moving toward the outlet opening 48 of the inlet duct 14 . The first ridge 60 is operable to impart a velocity component to said airflow 22 complementary to the tangential velocity of each of the first and second rotors 36 and 38 during rotation of the first and second rotors 36 and 38 . The first ridge 60 is preferably positioned immediately downstream of the bypass passage 30 .

Similarly, a second ridge 62 is formed centrally on the roof portion 52 and extends toward the outlet opening 48 of the inlet duct 14 . The second ridge 62 is preferably formed with a generally triangular cross-section with increasing height and width moving toward the outlet opening 48 of the inlet duct 14 . The second ridge 62 is operable to impart a velocity component to said airflow 22 complementary to the tangential velocity of each of the first and second rotors 36 and 38 during rotation of the first and second rotors 36 and 38 . Preferably the first and second ridges 60 and 62 are separated, at least initially, to allow the airflow 22 on each side of the first and second ridges 60 and 62 to equalize; however, the first and second ridges 60 and 62 can be designed to converge to form a septum at the outlet opening 48 of the inlet duct 14 .

In instances where the throttle body 20 is tilted with respect to the inlet duct 14 , the airflow 22 may be biased to one side of the inlet duct 14 by the throttle body 20 . In this case, the inner wall 42 may be shaped to bias the airflow 22 to the other side to balance the distribution of airflow 22 within the inlet duct prior to entering the inlet opening 32 of the compressor 12 , shown in FIG. 2 .

Referring to FIG. 4 , there is shown an alternate embodiment of the inlet duct 14 of FIGS. 1 and 3 , indicated at 14 A. The inlet duct 14 A has substantially the same structure as the inlet duct 14 , with the exception that a bypass passage 30 A is defined by the inlet duct 14 A and extends through the sidewall 54 of the inlet duct. Since the bypass passage 30 A does not intersect the floor portion 50 , the first ridge 60 may extend from any point between the inlet opening 46 , shown in FIG. 3 , and the outlet opening 48 of the inlet duct.

While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.